The character of Chuck is referred to in this episode when Richie (Ron Howard) mentions "my brother, my kid sister, and I" while talking to the burglar (Herbert Edelman).
This is not the last time the character of brother Chuck is mentioned. He is mentioned one more time in this season.
When Richie, Potsie, and Ralph are talking in Richie's room, they're standing in front of a Daytona 500 poster featuring a Confederate flag. In the reruns, the flag is intentionally blurred.
The Asiatic flu epidemic hit the U.S. in June of 1957.
Logic would dictate that when Potsie and Ralph drop by while the burglar is hiding in the closet that Richie just flee the house when he answers the door.